When it comes to major depressive disorder vs. bipolar disorder, the two can look similar at first; however, they affect mood, energy, and functioning in very different ways. This guide breaks down the symptoms, causes, and treatment options for each, so you can have a better understanding of what you or someone you love might be experiencing.
What is Major Depressive Disorder?
Major depressive disorder (MDD) is a mental health condition that affects how someone thinks, feels, and functions in their day to day. It’s classified as an episodic mood disorder, which means that symptoms appear in cycles called depressive episodes.
A recent study found that the lifetime prevalence of MDD is 7.5% for men and 13.6% for women, and the risk by age 75 rises to 20.1% for men and 34% for women. In other words, more than one in five people will experience at least one depressive episode in their lifetime.
Symptoms of Depression
Common symptoms of depression include:
- Persistent sadness, emptiness, or hopelessness
- Loss of interest or pleasure in usual activities
- Fatigue or lack of energy
- Sleeping too much or too little
- Changes in appetite or weight
- Difficulty concentrating or making decisions
- Feelings of guilt or worthlessness
- Thoughts of death or suicide
These symptoms must last at least two weeks for an official diagnosis, but for some, they can continue on for months without treatment.
Causes of MDD
Depression develops from a mix of biological, environmental, and psychological factors:
- Imbalances in neurotransmitters such as serotonin, norepinephrine, and dopamine can disrupt mood regulation
- Chronic stress, unresolved grief, or a history of trauma can increase vulnerability
- Perfectionism, rumination, and self-critical thinking can perpetuate depressive symptoms
Evidence also connects depression with inflammation in the body. Research shows that people with MDD often have elevated inflammatory biomarkers such as C-reactive protein (CRP). This shows the role the immune system has in mood regulation.
What is Bipolar Disorder?
Bipolar disorder is a mental health condition that causes extreme changes in mood and energy levels. These are much more intense than the highs and lows most people experience. A person with bipolar disorder may feel on top of the world during a manic episode, then deeply depressed during a depressive one, with periods of stability in between.
It’s estimated that about 5.7 million adults in the U.S., or 2.6% of the population, live with bipolar disorder each year. While it’s sometimes referred to as manic-depressive disorder, the modern understanding of bipolar disorder recognizes a few different types:
- Bipolar I
- Bipolar II
- Cyclothymic disorder (Cyclothymia)
- Other types not defined by the above
Bipolar Disorder Symptoms
Bipolar disorder includes manic (or hypomanic) and depressive episodes. Here are some common symptoms for each type of episode:
Mania or hypomania symptoms:
- Feeling unusually energetic, euphoric, or irritable
- Sleeping much less than usual but still feeling wired or alert
- Talking rapidly or feeling like your thoughts are racing
- Being easily distracted or unable to stay on one topic
- Showing poor judgment or taking impulsive risks
- Feeling overly confident or invincible
Major depressive episode symptoms:
- Feeling sad, empty, or hopeless
- Losing interest in usual activities
- Noticeable changes in appetite or weight
- Sleeping too much or too little
- Feeling exhausted or slowed down
- Difficulty concentrating or making decisions
- Feelings or guilt, shame, or worthlessness
- Thoughts of death or suicide
Some people experience additional symptoms like anxious distress, psychosis, or mixed episodes, where symptoms of depression and mania happen at the same time. Others experience rapid cycling, which means having four or more mood episodes within a single year.
Causes of Bipolar Disorder
Research shows that bipolar disorder is highly genetic, with findings reporting it to be between 70% and 90% heritable. In many cases, people with a family history of mood disorders have a higher risk of developing bipolar disorder themselves.
Bipolar disorder also involves chemical imbalances in the brain, especially in neurotransmitters like serotonin, dopamine, and norepinephrine. These chemical messengers help regulate sleep, mood, energy, and emotional processing. When they’re disrupted, it can trigger mood swings and instability.
Environmental factors can also contribute. Stressful life events, major changes, or lack of sleep can trigger episodes in people who are genetically vulnerable.
Can You Have MDD and Bipolar?
MDD and bipolar disorder share many symptoms, especially during a depressive episode; however, the presence of hypomanic or manic episodes signals bipolar disorder. If someone experiences elevated mood, more energy, or impulsive behavior that lasts for days or weeks, it’s not just depression, and these types of behaviors are what separate MDD from bipolar.
Misdiagnosis for Depression and Bipolar Disorder
Misdiagnosis between depression and bipolar disorder is unfortunately common, and it can delay proper treatment for years. Research shows that nearly 70% of people with bipolar disorder are initially misdiagnosed, usually as having major depressive disorder. Also, one-third or more still haven’t received an accurate diagnosis a decade later.
This happens because depression is often the first and sometimes only symptom that appears early on. Without visible manic or hypomanic symptoms, doctors may not see the full presentation.
Sadly, when bipolar disorder is treated as depression alone, antidepressants can sometimes destabilize mood and increase the risk of manic episodes. That’s why a thorough evaluation, including family history and mood tracking, is necessary before starting treatment.
Treatment for Bipolar and Depression
Because antidepressants can trigger mania in bipolar patients, treatment is slightly different when it comes to medications. Those with MDD are typically prescribed SSRIs, SNRIs, and atypical antidepressants, whereas doctors prescribed individuals with bipolar mood stabilizers (e.g., lithium, lamotrigine, or valproate) and/or atypical antipsychotics (e.g., quetiapine and lurasidone).
Both conditions typically improve with some type of psychotherapy, with popular ones being cognitive behavioral therapy (CBT), interpersonal therapy (IPT), or family therapy. The goal in therapy is to address negative thought patterns and learn healthier ways of coping and communication.
Recent evidence has shown that TMS therapy may be safe and effective for individuals with bipolar II disorder, showing promising results in reducing depressive symptoms. However, more research is needed before it can be approved by the FDA for the treatment of bipolar disorder.
Suicide in Depression and Bipolar Disorder
Both depression and bipolar disorder carry a high risk of suicide. Studies show that the risk of dying by suicide is about 8.6 times higher in major depression and bipolar disorder compared to the general population.
Among people with bipolar disorder, up to 50% attempt suicide at least once, and 15-20% die by suicide. Unlike overall suicide trends, rates in bipolar disorder haven’t declined in recent years.
Healing is Possible With Cura Behavioral Health
Whether you have major depressive disorder or bipolar disorder, you don’t need to “fix” yourself. At Cura Behavioral Health, we teach you how to work with your mind instead of against it. Here, treatment is a partnership, not a prescription. From medication management to talk therapy, our team is committed to delivering the compassionate care you deserve.
Ready to learn more? Reach out today and take the first step towards healing that lasts.
Sources:
- Global, regional, and national burden of major depressive disorders in adults aged 60 years and older from 1990 to 2021, with projections of prevalence to 2050: Analyses from the Global Burden of Disease Study 2021 – Journal of Affective Disorders
- The link between systemic inflammation and mental disorders: a study on CLR, depression, and anxiety in a US cohort – Frontiers in Psychiatry
- Bipolar Disorder Statistics – Depression and Bipolar Support Alliance
- Genetic Liabilities Differentiating Bipolar Disorder, Schizophrenia, and Major Depressive Disorder, and Phenotypic Heterogeneity in Bipolar Disorder – JAMA Psychiatry
- Neuromolecular Etiology of Bipolar Disorder: Possible Therapeutic Targets of Mood Stabilizers – Clinical Psychopharmacology and Neuroscience
- Bipolar Disorder Often Misdiagnosed as Major Depression, Leading to Improper Treatment – U.S. Medicine
- Transcranial Magnetic Stimulation in Bipolar II Disorder Treatment: A Case Report – Cureus
- Risk of suicidal behavior in patients with major depression and bipolar disorder – A systematic review and meta-analysis of registry-based studies – Neuroscience & Biobehavioral Reviews
- Why are suicide rates so high in bipolar disorder, and what can we do about it? – The Conversation
